Application Domains VoLTE



Transmitting voice packets with real-time requirements over a radio interface is a challenging task. Moving users, handovers, codec changes, varying radio conditions – just to mention the most obvious issues. LTE makes no difference.

But particularly speech transmission needs steadiness from beginning to end to deliver an excellent user experience. This is why a simple average quality summary per call does not help when assessing call quality.

VoLTE monitoring must not only deliver information on the control plane and S11 signaling, but also fixed-duration summaries of the speech quality.

Qrystal generates smart atoms (5-second summaries) for every RTP stream. In this way, the data can be used to determine for example

  • The quality of single calls or call directions
  • The quality of cells, eNBs, eNB clusters, or regions
  • The quantification of detected patterns
  • The impact of codec mode and bitrate change on call quality

Use cases of Voipfuture VoLTE monitoring

    1. Pre-deployment assessment
    2. RAN/EPC health check
    3. VoLTE troubleshooting
    4. Cell planning and optimization
    5. Analysis of bearer management
    6. Customer Care




Even in times of Unified Communications the phone service is still the most important means of communication. Bad voice quality generally affects productivity when talking to coworkers, customers, and business partners. It is inacceptable for call centers where the primary business objective is talking to customers.

Voice quality issues encountered by enterprises and public agencies often have the following root causes:

  • Hidden issues within the CSP’s network
  • Insufficiently sized inter-site and access network links
  • Legacy networks in old sites, small branch offices and factories
  • Variety of problematic end-devices including fax machines, Wi-Fi phones, and softphones


The complexity of identifying responsibilities and root causes is further increased in the presence of managed services where one IP infrastructure is used to deliver services by different providers.

Qrystal enables enterprises and public agencies to:

  • Provide detailed documentation for the voice quality of each individual call
  • Alarm in case of problems
  • Quickly identify the root causes of problems
  • Pinpoint responsibilities in shared infrastructure and interconnection scenarios

These capabilities are critical to the successful management and operation of any enterprise VoIP service. In addition, unique Qrystal KPIs allow enterprises to verify and document the user experience and service performance, thus putting them on a par with their CSPs.

IPX / Wholesale


IPX / Wholesale

IPX and international wholesale services, have been undergoing deep changes in recent years.

  • The industry players are no more limited to domestic Telcos and international Carriers
  • Price per minute has hit rock bottom, total minute volume is declining
  • OTT services established as a no-cost alternative

In consequence, the business targets shifted:

  • Focus on high-quality user experience as main differentiator
  • Attract additional flows of traffic (e.g. from OTT Providers)
  • Select better downstream operators
  • Allow an improved SLA management and reduce customers’ complaints

Qrystal offers IPX/Wholesale Carriers

  • an integrated real-time call monitoring function for user plane (media) and control plane (signaling)
  • non-intrusive time slicing technology, providing a wide range of information (codec, IP routing information, packet loss, jitter, etc.)
  • unique insights into the internal network performance and the performance of the interconnection partner

IMS Fixed

Favicon_Application Domains-86x86

IMS Fixed

Customers appreciate the value-added services of NGN and IMS networks, yet their baseline expectation regarding call quality is predetermined by the traditional PSTN. In other words, CSPs can only gain a competitive edge, if they maintain excellent voice quality.

However, there are many potential reasons for service degradations. Impairments can originate in a CSP’s own network as well as in the networks of customers and interconnection partners. Isolating a problem source – particularly if it is not in your own network – can be a challenging task.

Qrystal is essential for keeping voice service quality under control. It enables CSPs to:

  • Monitor and document the speech quality of all actual VoIP calls
  • Optimize their networks
  • Offer service level agreements (SLA) for voice quality
  • Quickly identify the root causes of problems
  • Pinpoint responsibilities in shared infrastructure and interconnection scenarios

These capabilities are critical for guaranteeing a premium voice service whilst ensuring an efficient use of resources.

Single Sided Calls

Favicon_Application Domains-86x86

Single Sided Calls

Everyone has experienced this

  • You can be heard, but you don’t hear incoming audio
  • Or vice versa
  • Or both

Whether it’s called single-sided call, one-way voice or silent call: For operation teams this is a hard problem.

To solve one-way voice you need to know the different reasons, for example

  • Missing RTP
  • Silent RTP
  • Too many RTP streams
  • Irregular RTP streams

Voipfuture Qrystal’s monitoring technology provides invaluable help. It is able

  • To automatically detect reasons for one-way voice
  • To help qualify the root-cause & quantify the impact

Monetizing MOS

Favicon_Application Domains-86x86

Monetizing MOS

Voice service monitoring is often tactical in nature. Tools produce data that is used by operations to work on customer tickets and to generally ensure that the network and service performs as designed. Any Return of Invest (ROI) mainly comes from savings due to higher operational efficiency.

But why not use the existing data in other areas to increase revenue and reduce cost? Qrystal and Qrystal Intelligence are successfully used by operations and performance optimization teams. On top, information provided by Qrystal is also used by CSPs to increase brand value and revenue by providing customers with access to their own service quality data.

Here’s why transparency pays off:

  • Differentiation (few CSPs are confident about their data)
  • Potential to sell data as a service
  • Fewer tickets (if data proves that problems originate in customer network)
  • Potential for selling troubleshooting services to customers
  • Customers love it

Of course, transparency can only work, if you can be confident that your data matches the user experience. The MOS and other media and signaling KPIs provided by Qrystal pass this test with ease.

Mean Opinion Score (MOS) - Calculation & Aggregation